Impact tool with magnetic base



J. H. BROWN 2,924,871

IMPACT TOOL WITH MAGNETIC BASE Feb. 16, 1960 Filed Oct. 29, 1956' 5 Sheets-Sheet l Jack H. Brown IN VEN TOR.

4 BY @Mm Feb. 16, 1960 J. H, BROWN 2,924,871

IMPACT TOOL WITH MAGNETIC BASE v Filed Oct. 29, 1956 I 3 Sheets-Sheet 2 as" Jack H. Brown INVENTOR.

I i *1 BY ua/0a W Em Feb. 16, 1960 J. H. BROWN IMPACT TOOL WITH MAGNETIC BASE Filed Oct. 29, 1956 Fig.4

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Jack H. Brown INVENTOR.

BY Q v United States Patent invention relates in general to new and useful improvements in impact tools, and more specifically to an" improved" impact" tool having a magnetic base for the" mounting of the impacttool during use.

Aboard ship there is thecontinuousproblem of keeping the steel", plates of the ship clean and painted. Because of'theaction ofthe' seawater, unless the surface of the ships plates is absolutely clean when the new paint surface is'applied, theplates willcontinue to rust beneath the new paint surface and as a result the new paint will eventually spalll cit. In order that the surface of the ship plates may be'properlycleaned, at the present time it; is necessary thatthe surface be cleaned withtripping hammers. which are manually operated. The surface is then finally cleaned with a wire brush or the like; However, this requires a relatively great expenditure of manual labor which could be saved with an automatic machine.

Itis therefore the'prim ary object of this invention to provide animprovedimpact' tool'which is so constructed whereby it is effective in the operation of chipping paint and scale from ships plates, the tool being provided with a; plurality of' ir'npact heads which will' strike the plates with. only sufficient force to remove the paint and scale from the plateand" innoway mark or mar the plates.

:An'oth'er object of. this inventionis to provide an improved. impact" tool, the impact tool being primarily intended for removing p'aintand scale from steel plates and including a magnetic base whereby the impact tool may be self-supporting, the' tool because of' the magnetic base.being suitablelfor chipping paint and scale on sides of ships and overheads of ships.

I Another object of this invention is to provide an improvedv impact tool,.the' impact tool being provided with impact heads mounted'on' shafts; the shafts having asso-- ciated'; therewith driving rods, the driving rods being reciprocated' by crank means and having an effective stroke which is less thanthe travel of the impact head sorthatf there, is nodirectmechanical connection between thedriving. rods and the impact heads at the time the impact heads strike a'worlc surface-thereby eliminating undesirable forces on the driving rods and the means for.reciprocating the driving rods.

A further objec't'of this invention is to'provide an improved impact: tool which'is provided with a magnetic b'ase,.the impact tooll being driven by an electric motor andithe. magnetic basejbeing of'the electro-magnetic type 2,924,871 Patented Feb. 16, 1960 details of construction and operation as more fully here inafter described and claimed, reference being'had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which: Figure 1 is a side elevational'view of the impacttool which is the subject of this invention and shows generally the details thereof;

Figure 2 is an end view of theimpa'ct tool of Figure 1' and shows the driving connection betweenthe electric power unit of the impact tool and'crank thereof, lowered positions of impa'ctheads of the impact tool being shown by dotted lines;

Figure} is a bottom view of the impact tool taken substantially upon the plane indicatedby the sectionline- 3-3 of Figure 2 and shows the relationship ofthe various impact heads with respect to the magnetic base;

Figure 4 is a vertical sectional view taken substantially upon the plane indicated by the section line 4-4 of Figure l and shows the specific relationship between the crank, the connecting rods, the driving rods, the

impact headsand shafts supporting the impact heads;

Figure 5 isa transverse horizontal sectional view taken substantially upon the plane indicated by the section line 5-5 of Figure" 1 and shows further the relationship of shafts for the impact heads and guide sleeves on which they aremounted for guided movement; and

Figure 6 is a p'erspective'view of one of the impact heads and the shaft on which it is mounted.

Referring now to the drawings in detail, it will be seen that there is illustrated the impact tool which is the subject of this invention, the impact tool being referred to ingeneral by thereference numeral 10. The impact tool 10 includes a base, which is referred to in general by the reference numeral 12, and a supporting frame whichis referred to in general by the reference numeral 14.

The supporting frame 14 includes a bottom plate 16 which is generally rectangular in outline. Extending upwardly from the bottom plate from positions adjacent the corners thereof, as is best illustrated in Figure 5 is a plurality of" vertical supports 18. The upper ends of the'vertical supports 18 are connected to a top plate 20 which is similar to the bottom plate 16. The vertical supports 18 are connected together intermediate their ends by an intermediate plate 22.

Secured to the outer faces of the vertical supports 18- at opposite ends of the supporting frame 14 are crank supporting plates 24. The cranksupporting plates 24 have extending upwardly therefrom rods 26 which include intermediate journal portions 28. on the journal portions 28 are bearing carrying bars 30.

the'uppe'r ends ofthe rods 26 and locked in adjusted positions. by means of set screws 38. By varying the posi tions of the collars 36, the tension of thesprings 32' ant. 34- may be selectively varied to' vary the shock dampening properties' of the bearing carrying bars 302 Carried=by the bearing carrying bars 30 are aligned: bearings40in which there are mounted for rotation.

longitudinallyextencling cranks 42; In order that the cranks-'42 may be driven, there is secured to the top plate 20 of the supporting' frarne l l' a-power unit in the form of'an electric motor 44. The electriclrnotor. 44

has connected thereto a flexible electric wire 46- so that) the'impact tool lfl 'may be readily moved from' place to place during a work operation therewithz- The: op'er- Slidably mounted" 3 ation of the electric motor 44 is controlled by means of a switch 48.

The electric motor 44 includes an armature shaft 50 which extends out through opposite ends thereof. Mounted on opposite ends of the armature shaft 50 are pulleys 52 and 54. The pulleys 52 and '4 are aligned pulleys 56 and 58, respectively, of the cranks 42. Entrained over the pulleys 52 and 56 are drive belts 60. Similar drive belts 62 are entrained over the pulleys 54 and 58. It is pointed out at this time that the cranks 42 are identical and one of the cranks 42 may be substituted for the other by merely rotating it 180 degrees and placing it in position. By so making the cranks 42, the ends thereof may be offset as is illustrated in Figure l and still permit the interchangeability.

Carried by the intermediate plate 22, as is best illustrated in Figure 4, is a plurality of guide sleeves 64. The guide sleeves 64 are arranged in groups, there being one group of guide sleeves 64 for each of the cranks 42. Mounted in the upper part of each guide sleeve 64 for guided reciprocation is a driving rod 66. Connected to the upper end of each driving rod 66 by means of a pm 68 is a connecting rod 70. Each of the cranks 42 s provided with a plurality of throws 72, as is best illustrated in Figure 1. The throws 72 are so spaced whereby they are disposed on opposite sides of each of the connecting rods 46. Extending between the throws 72 1s a journal pin 74 on which the upper end of each connecting rod 70' is mounted. Thus as the cranks 42 rotate, the driving rods 66 are reciprocated within the guides 64.

The bottom plate 16 is provided with bores 76 which are aligned with the guide sleeves 64. Slidably passing through the bores 76 are shafts 78. The upper ends of the shafts 78 are received in the lower ends of the guide sleeves 64 for guided reciprocatory movement. The lower ends of the shaft 78 are provided with impact heads 80. The impact heads 80 are disposed beneath the bottom plate 16 and have the upper parts thereof normally retained in engagement with the underside of the bottom plate 16 by the action of coil springs 82.

The coil springs 82 are telescoped over intermediate portions of the shaft 78 and are retained in place by collars 84 removably pinned on the shaft 78. Thus the coil springs 82 serve to retain the impact heads'80 and the (shaft 78 in a retracted position as illustrated in Figure As is best illustrated in Figures 2, 3 and 4, it will be seen that the base 12 is in the form of a pair of longitudinally extending blocks 86 disposed at opposite sides of the impact tool and extending longitudinally thereof. The blocks 86 are of a desired height and support the impact heads 80 out of engagement with a work surface, such as the work surface 88 and at the same time to permit the driving rod 66 to move the impact heads 80 into striking engagement with the work surface 88. In order that the operator of the impact tool 10 need not support its weight during a working operation, there is mounted in each of the bars 86 powerful electro-magnets 90. The electro-magnets 90 will be of sufficient strength to support the impact tool during its operation either from a. vertical surface or an overhead horizontal surface. Thus when the impact tool 10 is to be used in a chipping operation either on the side of a ship or an overhead of the ship, the electro-magnets 90 will be suflicient to support the impact tool in place once it has been positioned by the operator. The electro-magnets 90 are energized by means of a wire 92 which is connected to the lead wire 46 of the electric motor 44. for the operation of the electric motor 44 may control the energization of the electro-magnets 90.

Referring once again to Figure 4, it will be seen that for a major portion of its stroke, each driving rod 66 is disposed out of engagement with its associated shaft 78. Thus as the driving rod 66 approaches the lower end of If desired, the switch 48' its stroke, it firmly comes into engagement with the upper ends of the associated shaft 78. Further, the effective length of the stroke of eachjdriving rod 66 after its engagement with its respective shaft 78 is less than the distance between the impact head and the work surface 88. By so arranging the components of the drive means of the impact head 80, it will be seen that there is no direct mechanical connection between the cranks 42 and the impact heads 80 at the time the impact heads 80 engage the work surface 88. However, the shaft 78 and the impact heads 80 are driven downwardly with sufficient force by the driving rod v66 to accomplish the desired operation. It is to be understood that the mating portions of the driving rods and theshaft 78 will be formed of such material so as to prevent upsetting thereof.

At this time it is pointed out that two cranks 42 have been illustrated and that each of the cranks 42 drive-four impact heads 80. If desired, the number of cranks 42 may be varied so as to be increased or decreased and each crank 42 may drive a greater or lesser number of impact heads. The only limitations placed upon the number of cranks 42 and the number of impact heads 80 is that the impact 10 should remain portable and readily handled by one man.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modificationsand equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A portable impact tool comprising a supporting frame, a power unit supported by said frame, a plurality of parallel first guides carried by said frame, first shafts slidably mounted in said first guides, a plurality of second guides axially aligned with respective ones of said second guides, second shafts slidably mounted in said second guides, impact heads on said first shafts remote from said power unit, springs engaged with said first shafts and continuously urging said first shafts to retracted positions, a crankshaft, means carried by said frame supporting said crankshaft in transverse alignmentwrth sa d second shafts, connecting rods connecting sa1d second shafts to said crankshaft for continuous reciprocation and periodic engagement with said first shafts, and means connecting said drive unit to said crankshaft for rotating said crankshaft. I 2. A portable impact tool comprising a supporting frame, a power unit supported by said frame, a plurality' of parallel first guides carried by said frame, first shafts slidably mounted in said first guides, a plurality of second guides axially aligned with respective ones of said second guides, second shafts slidably mounted in said second guides, impact heads on said first shafts remote from said power unit, springs engaged with said first shafts and continuously urging said first shafts to retracted positions, a crankshaft, means carried by said frame supporting said crankshaft in transverse alignment with said second shafts, connecting rods connecting said second shafts to said crankshaft for continuous reciprocation and periodic engagement with said first shafts, means connecting said drive unit tosaid crankshaft for rotating sa d crankshaft, and a base on said frame remote from said power unit, said base being of the peripheral type and extending about said impact heads, said impact heads being entirely retracted within said basev by said springs.v

UNITED STATES PATENTS 1,828,791 Thompson Oct. 27, 1931 710,257 De Leeuw Sept, 30, 1902 2,263,595 inkko Nov. 25, 1941 1,115,348 Taylor Oct. 27, 1914 2,356,314 G ray Aug. 22, 1944 6 ,101 Colson July 17, 192 ,477 Kmd Aug. 22, 1950 1,481,906 Jackson Jan. 29, 192 5 ,5 3,348 Briese Feb. 27, 1951 6,889 Wright Oct. 13, 1925 53,435 Briese May 15, 1951 1,745,100 Johnston Jan. 28, 1930 2,562,899 Finn Aug. 7, 1951 1,813,087 Sandage July 7, 1931 2,779,085 Schoengarth Jan. 29, 1957 

